Game Balance Rules - Heliomance/Uncharted-Horizons GitHub Wiki
Design document §6
Each game generates a set of World Truths at creation (Section 5). Breakthroughs are absent from a game in two ways: the Removal Truths (historically called Removal Flags) delete them, and the foundational axes leave no room for the branches belonging to the values a world did not draw; the frontier axes, and the rival theories a decisive experiment settles, leave breakthroughs present but decide whether they validate or dead-end (Section 1.2 sets out all three). Removal Truths and the RARE-easing Enabling Truths (Enabling Flags) are summarised here; the Foundational and Frontier axes are detailed in Section 5.
Removal Truths remove specific breakthroughs. Their key interaction is with Competing Solutions: an alternative whose primary is removed loses its detour margin, takes the primary's tier and can never be locked out — it becomes the way.
- GUNPOWDER_ABSENT: ~15% of games. WA10 (Gunpowder) and all gunpowder-dependent breakthroughs removed. No UNCOMMON alternative — the alternative weapons (crossbow, pneumatic, railgun) are entirely different branches.
- FOSSIL_FUELS_ABSENT: ~10% of games. MI06 (Coal) and MI07 (Petroleum) are removed, and with them Petrochemistry (CH09), which needs Petroleum. The Blast Furnace (ME08) and the Internal Combustion Engine (MC09) open without them — by charcoal and by distilled alcohol — and their Charcoal Kilns and Distillery Fuel Depots make the Coal and Oil, which the Coal and Oil Power Plants then burn. Bio-Organic Synthesis (CH09-W) can never be locked out there, its primary being absent, which makes it the primary chemistry path; the Biomass and Bio-Fuel Plants remain Competing Solutions, as in every world.
Note that fusion is not a Removal Truth in the current model: it is governed by the Frontier axis FQ2 (Fusion Practicality), whose Impossible value (~25% of games) reproduces the old FUSION_ABSENT experience — NP04 and its dependents never validate, and the deep fission chain (NP-F01+) can never be obsoleted. The Marginal value (~15%) is a softer outcome the old flag couldn't express: fusion works but underperforms, keeping deep fission competitive. Legacy "FUSION_ABSENT" references elsewhere in the document denote the FQ2-Impossible world.
Enabling Truths don't remove anything. Instead, they make certain RARE gateway breakthroughs significantly easier to discover — effectively lowering them to UNCOMMON difficulty while set.
- AEOLIPILE_VIABLE: ~15% of games. MC07 (Hero's Aeolipile) treated as UNCOMMON difficulty instead of RARE. Early steam becomes a realistic possibility in the Classical era.
- ENHANCED_SPRINGS: ~15% of games. MC15 (Mainspring Energy Storage) treated as UNCOMMON difficulty instead of RARE. The entire Clockwork path becomes dramatically more viable.
- ANTIKYTHERA_TRADITION: ~20% of games. O10 (Antikythera-Style Mechanism) treated as UNCOMMON difficulty instead of RARE. The analog computation chain becomes accessible.
Truths combine: ~2% chance of Enhanced Springs + No Fossil Fuels ("clockpunk"), ~3% chance of Antikythera + Enhanced Springs ("mechanical computing"), etc. All twelve axes (Section 5) are sampled together, subject to master-axis derivation and constraint-checking. FTL method selection (FQ1) is not independent of the other axes: it is sampled after the Matter axis (FQ9), from the five methods valid for that world (D atomic-only, F elemental-only), and then derives the frontier truths as Principle 3 (Section 5) describes.
- At least one complete path from Primitive to Interstellar using only CORE breakthroughs, regardless of which World Truths are set. No terrain condition stands on it (v3.117–v3.118): its only environmental conditions are iron in territory, which trade or conquest can supply (§1.2), and a city of five (Specialization of Labor)
- Exactly one FTL method viable per game, its build and prove rows always CORE or STANDARD in that world. Six methods exist; Tunnelling is atomic-only and Plenum elemental-only (a matter-axis mirror pair), so each world offers five candidates. World creation draws the viable method and the world's conditions by §4's Generation Rules, whose guarantee keeps the viable method's build and prove rows reachable whatever the world's other truths; the universal methods' atomic rows resolve to their Quintessic equivalents per FTL in Elemental Worlds (§4). Power for the brute-force methods (W9) is always reachable: three ES06 Nuclear Fission Plants (CORE) match one advanced fission plant, as do ES14 Advanced Fission or ES08 Fusion alone; in elemental worlds, ES15 Quintessic Plants or QM-E05 (Re-Tempering Reactor).
- At least one energy path to Space-era power levels — the Nuclear Fission Plant (ES06, CORE) in Corpuscular worlds, the Quintessic Power Plant (ES15) fed by Bound-Energy Release (QM-E02, CORE) in Elemental worlds
- Writing (SO04) or alternative (SO09) always available
- At least one metal (copper or iron) always available via S04 + F04. Strategic resource trading allows access without local deposits.
- Scientific Method (PH04) always available
- At least one ranged weapon path reaches Modern era (crossbow is STANDARD and always discoverable)
- Mass iron/steel production always achievable: the Blast Furnace (ME08) is CORE and opens with either fuel, Coal Discovery or Charcoal Production, and with either mill, the Water Mill or the Windmill, so it exists in every world and needs no river. Where there are no coal seams, its Charcoal Kilns make Coal from worked fuel tiles — Forest, Jungle or Peat Cutting — and trade can supply the rest (§1.2).
- Vehicles/motorisation always achievable: the Internal Combustion Engine (MC09) is CORE and opens with either fuel — petroleum, or distilled alcohol — so it exists in every world. Where there are no wells, its Distillery Fuel Depots make Oil from worked Farms, and trade can supply the rest (§1.2).
- Polymer/materials science path always reachable (CH09-W bio-organic synthesis, a STANDARD Competing Solution; in FOSSIL_FUELS_ABSENT worlds its primary is absent, so it has no detour margin and can never be locked out). Its prerequisites are CORE and STANDARD only: Mycological Knowledge speeds it but is not required.
- World Truth sampling is constraint-checked: after axes are sampled (Section 5), the generator verifies rules 1–10 hold; violating combinations are re-sampled. The FTL master axis derives dependent truths so contradictory worlds cannot exist.
- Victory is never dice-locked: every breakthrough required for the viable FTL method is CORE or STANDARD, all of which can be Revealed through theory or proximity, and any Revealed breakthrough with Discovered prerequisites can be completed deterministically as a Grand Endeavour (Section 1.5), whether or not its idea has occurred. A STANDARD idea the victory waits on comes back by itself if its moment passes (rediscovery on demand, §1.2, v3.120). A player who pursues victory methodically cannot be stopped by chance — only slowed by it.
See Section 1.2 for full details. Summary:
- After the Printing Press: CORE and STANDARD breakthroughs held by half a civilisation's contacts arrive free 10 turns later
- After the Internet: 5 turns, UNCOMMON included; RARE never diffuse, and what the old roll bonuses become is proposed, not decided (§1.2)
- UNIQUE breakthroughs are always exempt from diffusion
When a breakthrough under study passes four-fifths of its meter: "Your scholars report promising developments in [Focus Area]..." (the focus, never the breakthrough: meters stay hidden).
- Trading: Breakthrough can be traded between civs. Recipient gains 75% effectiveness until they accumulate matching Insight through their own research (representing full local understanding).
- Espionage: Stolen breakthroughs operate at 50% effectiveness.
- Reverse Engineering: Chance from captured units/cities.
- UNIQUE breakthroughs: Cannot be traded or stolen. The special buildings, units, and abilities from UNIQUEs are exclusive to the discovering civilisation. Other civs can see the effects but cannot replicate them. This is the primary mechanism for civilisation differentiation in the mid-to-late game.
- Strategic Resources: Active trade agreements importing a resource count as "in territory" for prerequisite purposes. Losing the agreement means losing access.
Every Competing Solutions group (§1.2). Each alternative is STANDARD with a detour margin of ×1.5 while its primary exists in this world; discovering the primary first locks the alternative out for that civilisation.
| Goal | Primary | Alternative | If the primary arrives later |
|---|---|---|---|
| Spanning a roof | Arch Construction (CO03) | Corbel Arch/Vault (CO05) | superseded |
| Mounted shock troops | Cavalry Tactics (WA07) | Chariot Warfare (WA08) | superseded |
| Bulk inland transport | Railway Network (CO23) | Industrial Canal Network (WM11) | superseded |
| A prime mover from fire | Steam Engine (MC08) | Atmospheric Engine (TH14) | superseded — no new Engine Houses; existing ones keep pumping until converted into a Steam Works |
| Industrial chemistry | Petrochemistry (CH09) | Bio-Organic Synthesis (CH09-W) | persists — it needs no Oil |
| Thermal power | Coal Power Plant (ES03) | Biomass Power Plant (ES03-W) | persists — it needs no Coal and makes no smoke |
| Flexible power | Oil Power Plant (ES05) | Alcohol/Biogas Power Plant (ES05-W) | persists — it needs no Oil |
| Power beyond basic fission | Nuclear Fusion (NP04) | Advanced Fuel Cycles (NP-F01) | persists — the deep fission chain it opens keeps its micro-reactors and endurance |
| The endgame plant | Fusion Reactor (ES08) | Advanced Fission (ES14) | persists — it is part of the deep fission chain |
| Fission fuel | Nuclear Fission Plant (ES06) | Thorium Reactor (NP08) | persists — it needs no Uranium and cannot melt down |
| A compact prime mover | Internal Combustion Engine (MC09) | Stirling Engine Mastery (TH08) | persists — it burns anything |
| Calculation | Programmable Computer (CP01) | Analog Computing Mastery (CP13) | superseded — but the perceptron road it opens persists |
| Machine intelligence | Artificial Intelligence (Narrow) (CP07) | Perceptron Machines (CP14) | persists — a city chooses a Perceptron Laboratory or an AI Lab |
| Treating infection | Antibiotics (MD06) | Phage Therapy (MD20) | persists — a city chooses a Phage Institute or a Medical Lab |
| Electrification | Power Grid (EL07) | Direct-Current Stations (EL14) | persists — it works where the network does not reach |
| Fixed nitrogen for the fields | Catalysis (CH12) | Nitrate Fertiliser (FA16) | superseded |
When a Removal Truth removes the primary, a foundational axis forecloses it, or a frontier axis dead-ends it (Nuclear Fusion in an FQ2-Impossible world), the alternative loses its margin, takes the primary's tier and can never be locked out — a dead-ended breakthrough locks out nothing. This is the core mechanism of the alternative industrial and energy paths: they add no breakthroughs; they protect existing ones from obsolescence.
Some breakthroughs can be discovered through multiple Focus Areas (noted on each breakthrough). These are discovered only once — whichever focus completes the study first claims it. This means a civilization investing in Farming might accidentally discover Catalysis (CH12) before a rival's Chemistry focus does.
Every dual path, as recorded on the focus pages: